Four-time Grand Slam champion Naomi Osaka said that she was in "shock" about fellow tennis star Peng Shuai, who has not been heard from since alleging that a powerful Chinese politician sexually assaulted her. Four-time Grand Slam champion Naomi Osaka said that she was in "shock" about fellow tennis star Peng Shuai, who has not been heard from since alleging that a powerful Chinese politician sexually assaulted her. Osaka added her voice to growing concern within tennis about Peng's fate, with men's number one Novak Djokovic and numerous other players in recent days saying they were deeply worried about her. The 24-year-old Osaka wrote a short statement on Twitter, where she has 1.1 million followers, accompanied by #WhereIsPengShuai -- a hashtag which has been widely used on social media.